FIG. 10.
FIG. 11.
PLATE II. To face pp. 26 and 27.
Prevention, however, is better than cure, and several machines are on the market fitted with stop motions to arrest the action of the machine at the breakage of a single end, and reducing the number of falling rods to two. One favourite system is to have a small bent wire, not unlike a hairpin, but about 1-1/4 inch in length, suspended from each thread and held in position by slots across the frame. This system is shown in [Plate II.], [Figs. 10] and [11]. Immediately under these pins are two nip rollers M ([Fig. 10]), revolving in contact, one of them borne on a movable centre, and attached to an upright lever N. This is immediately above an upright slide I, the bottom of which is connected to one end of a lever centred on the drum shaft of the frame. At the other end of the lever is a foot board and also the connection of a long rod with heavy balance weight always tending to press the footboard up, and consequently the slide down.
The machine is driven by a single open strap on the pulley, which, however, does not actuate the machine until it is pressed against the friction plate.
To start the machine, the footboard is pressed down, the slide consequently lifted and held in position by a hook which catches on the framework. By an inclined collar J, on the centre of the lever H ([Fig. 11]), the friction pulley and plate are pressed into contact and the machine is in motion. When an end breaks, the hair-pin drops between the nip rollers, pressing the loose one away from the other, therefore by means of the upright lever already referred to knocking off the catch H ([Fig. 10]). As soon as this is done the slide drops, and with it the lever O. The inclined collar relieves the pressure on the friction plate and the machine stops. The attendant pieces the broken end which is thus brought under his or her notice.
Beam warping machines are of various sizes, the most common being for 504 bobbins, the width being 9/8ths, or 54 inches between the flanges of beam. Other widths, of course, are in use, from 44 to 108 inches.
The waste of yarn, in the preparatory processes, indeed in all departments of mill work, is extremely important, and should be kept at as low a percentage as possible. At the winding frame the total waste should be 1 to 1-1/4 per cent., varying with the count and quality of yarn, and the total waste of warp yarn throughout the mill should not exceed 1-1/2 per cent. at the most.